Information was collected on 256 pathologically confirmed cases of Burkitt's lymphoma (BL) diagnosed in the western hemisphere. The curability of BL was confirmed, particularly in patients with limited disease. Target organs appeared to be related to age, suggesting a predilection of the disease for rapidly dividing cells. Laboratory and epidemiologic studies provided evidence for environmental as well as genetically determined predisposing factors. Patients with Epstein-Barr virus (EBV) associated tumors appeared to have a longer survival rate than those with non-EBV associated tumors.